Shock-absorbing seat structure

ABSTRACT

A seat-mounting structure including a stationary base in a generally horizontal seat-support assembly disposed above the base. Spring controlled pivoted levers and connecting links support the assembly above the base for vertical movement relative to the base between upper and lower limit positions while maintaining the seat support generally horizontally disposed. Controlling springs of the structure include a first pair of springs which are progressively tensioned as the seat support assembly is moved from its upper limit position to its lower limit position and a second pair of springs which are pretensioned and whose tensioned state remains substantially the same throughout movement of the seat-support assembly from its upper limit position to a lower intermediate position above the lower limit position and which are progressively further tensioned during movement of the seat-support assembly from the intermediate position to the lower limit position thereof.

United States Patent [72] Inventor Carl 1. Sedlock Box 145 Rte 1, Elwood, 111. 60421 [21] Appl. No. 842,613 [22] Filed July 17,1969 [45] Patented Aug. 31, 1971 [54] SHOCK-ABSORBING SEAT STRUCTURE 9 Claims, 5 Drawing Figs.

[52] U.S. Cl 248/399 [51] Int. Cl A47c 3/22 [50] Field of Search 248/399,

[56] References Cited UNITED STATES PATENTS 2,289,854 7/1942 Permann et a1 248/376 2,298,351 10/1942 De Rose 248/419 2,916,082 248/376 12/1959 Wilkinson et al Primary Examiner- Edward C. Allen Altorneys-Clarence A. OBrien and Harvey B. Jacobson position to its lower limit position and a second pair of springs which are pretensioned and whose tensioned state remains substantially the same throughout. movement of the seat-support assembly from its upper limit position to a lower intermediate position above the lower limit position and which are progressively further tensioned during movement of the seatsupport assembly from the intermediate position to the lower limit position thereof.

PATENTEU M1831 ISYI 3.6021475 SHEET 2 BF 3 Fig. 2

Carl P. Sad/oak INVI'JN'I'OR.

SHOCK-ABSORBING SEAT STRUCTURE The shock absorbing seat structure of the instant invention has been specifically designed to provide a support assembly upon which a seat cushion may be mounted and which will support the associated seat cushion for generally vertical movement between upper and lower limit positions with spring means being provided yieldingly urging the seat-support assembly toward its uppermost limit position. The spring means provided is connected between the seat-support assembly and the base from which the support assembly is mounted in a manner such that downward movement of the seat-support assembly is progressively resisted at a nonuniform rate as the seat-support assembly is shifted from the upper limit position thereof to the lower limit position thereof.

The seat-support assembly is supported in elevated position above the base by means of spring controlled pivoted levers and connecting links and the controlling springs include a first pair of springs which are progressively tensioned as the seatsupport assembly from its upper limit position to its lower limit position and a second pair of springs which are pretensioned and remain in substantially the same pretensioned condition throughout movement of the seat-support assembly from its upper limit position to a lower intermediate position spaced above the lower limit position and which, upon movement of the seat-support assembly from the intermediate position thereof to the lower limit position thereof, are also progressively tensioned. In actuality, the second set of springs tend to oppose the first set of springs with slight and diminishing force as the seat-support assembly moves from its upper limit position toward the intermediate position thereof.

The main object of this invention is to provide a seat-mounting structure which will be capable of supporting a seat cushion for vertical movement between upper and lower limit positions and which will yieldingly resist downward movement of the supported seat.

Another object of this invention is to provide a seat-mounting structure which will be particularly well adapted to yieldingly support the seat cushion of the operator of certain heavier vehicles such as trucks and buses.

Still another object of this invention is to provide a seat cushion supporting structure in accordance with the preceding objects and including novel spring controlled pivoted levers and connecting links for supporting the seat cushion supporting structure from a suitable base therefor for movement between upper and lower limit positions relative to the base.

It is another important object of this invention to provide a shock-absorbing seat structure for use in various environments but specifically adapted for use as the seat for the operator of trucks and buses and which will provide a spring mount for a seat cushion that will automatically compensate for the weight of the driver supported therefrom.

Another important object of this invention is to provide a spring support for a seat cushion which will afford a high degree of resiliency with a minimum amount of spring board" sensation.

A final object of this invention to be specifically enumerated herein is to provide a shock-absorbing seat structure in accordance with the preceding objects which will conform to conventional forms of manufacture, be of simple construction and dependable in operation so as to provide a device that will be economically feasible, long lasting and relatively trouble-free.

These together with other objects and advantages which will.

FIG. 2 is a rear elevational view of the seat structure as seen from the left side of FIG. 1; v

FIG. 3 is a fragmentary vertical sectional view taken substantially upon the plane indicated by section line 3-3 of FIG. 2 and with the seat support portion of the seat structure in its uppermost position;

FIG. 4 is a vertical sectional view similar to FIG. 3 but with the seat-support portion of the seat structure disposed in its lowermost position; and

FIG. 5 is a fragmentary exploded perspective view of the seat structure. v

Referring now more specifically to thedrawings, the seat structure of the instant invention is generally referred to by the reference numeral 10 and includes a baseplate l2 including-integral upstanding opposite flange portions 14 which are substantially identical except for being right and left handed.

The structure l0 includes a pair of right and left-handed main support levers 16 and a second pair of right and lefthanded levers or arms 18 in addition to a pair of upstanding connecting links 20. Each of the levers 16 includes a mounting arm portion 22 which projects upwardly therefrom intermediate its opposite end and the upper end of each mounting arm portion 22 is pivotally supported from the corresponding flange 14 by means of a pivot fastener 24. The front ends of the levers 16 are providedwith large diameter apertures 26 and the lower ends of the links 20 are pivotally connected to the rear ends of the corresponding levers 16 by means of pivot fasteners 28 secured through apertures 30 formed in the lower ends of the links 20 and apertures 32 formed in the rear end portions of the levers 16.

The forward ends of the levers 16 have a bar 34 secured therebetween by means of fasteners 36 threadedly engaged with the bar 34 and received through the apertures 26. A pair of spacing sleeves 38 are disposed on the opposite ends of the bar 34 inwardly of the front ends of the levers l6 and the rear ends of the levers 16 have a tubular bar 40 similar to the bar 34 secured therebetween by means of fasteners similar to fasteners 36. The seat structure 10 further includes a seat cushion supporting structure referred to in general by the reference numeral 42 and which includes a pair of opposite side elongated bars 44 having sleeves 46 secured through their forward end portions and journaled on the opposite ends of the bar 34 inwardly of the spacing sleeves 38. The rear ends of the bars 44 include inwardly directed sleeves 48 and an elongated bar 50 has its opposite ends secured through the sleeves 48 and the rear ends of the bars 44 by means of fasteners 52. A central sleeve 54 is journaled on the central portion of the bar 50 intermediate the adjacent inner ends of the sleeves 48 and a bifurcated crank arm 56 is mounted on the sleeve 54 and includes a pair of generally radially outwardly projecting furcations 58.

The forward ends of the bars 44 include upstanding apertured arms 60 whose upper ends are pivotally secured to the upturned forward ends 62 of the levers or arms 18 by means of pivot fasteners 64. The rear ends of the levers or arms 18 include rearwardly and downwardly inclined crossheads 66 whose upper ends are pivotally secured to the flanges 14 by means of fasteners 68 and whose lower ends have the upper ends of the connecting links pivotally secured thereto by means of suitable fasteners 70. Further, the front and rear ends of the bars 44 include inturned apertured horizontal mounting flanges 72 and 74.

A pair of sleeves 76 are disposed on and pinned to the opposite end portions of the bar 40 inwardly of the rear ends of the levers l6 and a center sleeve 78 is journaled on the central portion of the bar 40. A lever arm 80 has one end thereof secured to the central sleeve 76 and the free end of the lever arm 80 projects upwardly from the sleeve 78 and is pivotally fastened between the rear terminal ends of the rearwardly and downwardly inclined furcations 58 by means of a suitable pivot fastener 82.

Apair of anchors 84 are carried by the sleeves 48 and include apertures 86 formed therethrough spaced circumferentially about the sleeves 48. Further, the crank arm 56 includes a base end portion 88 provided with apertures 90 spaced circumferentially about the bar 50 and a pair of torsion springs 92 are disposed about the adjacent ends of the sleeves 48 and 54 and the portions of the bar 50 extending therebetween. The adjacent ends of the torsion springs 92 include laterally directed end portions 94 which are anchored in opposite end portions of a selected aperture 90 and the remote ends of the torsion springs include laterally directed end portions 96 which are anchored in corresponding apertures 86 formed in the anchors 84. 1

Also, the base end 98 of the lever arm 80 defines an anchor having apertures formed therethrough corresponding to the apertures 90 and the sleeves 76 include apertured anchors 100 corresponding to the anchors 84. A second pair of torsion springs 102 include laterally directed end portions 104 anchored in apertures formed in the base end portion 98 corresponding to the apertures 90 in the base end portion 88 and the remote ends of the torsion springs 102 include laterally directed end portions 106 anchored in suitable apertures formed through the anchors 100 corresponding to the apertures 86 formed through the anchors 84.

From a comparison of FIGS. 1-4 it will be appreciated that the torsion springs 92 tend to rotate the crank arm 56 in a counterclockwise direction as viewed in FIGS. 3 and 4 of the drawings and that the torsion springs 102 tend to rotate the lever arm 80 in a clockwise direction as viewed in FIGS. 3 and 4.

A pair of upwardly opening channel members or tracks 1 are secured to each pair of corresponding mounting ears 72 and 74 by means of suitable fasteners 112 and 114. A pair of slides 116 are slidably received within the tracks 110 for movement therealong and a seat back supporting structure referred to in general by the reference numeral 118 is secured to the rear ends of the slides 116 by means of suitable fasteners 120. The seat back structure 118 includes notched portions 122 which key with the adjacent flange portions 124 of the tracks 110 and the forward ends of the slides 116 include upstanding pins 126 receivable upwardly through apertured horizontal flange portions 128 carried by a seat cushion 130. A pair of journal sleeves 129 are secured to the front ends of the slides 116 and rotatably receive the opposite ends of an operating crankshaft 131 therebetween having a pair of cams 132 mounted thereon for engagement with the undersides of the flanges portions 128 whereby the forward edge portion of the seat cushion 130 may be adjusted in elevation. In addition, the front ends of the slides are interconnected by means of a transverse brace member 134 and a journaled sleeve portion 136 is supported from the crossmember 134 and rotatably receives an operating shaft 138 therethrough having a cam 140 on its rear end for engagement with a horizontal flange portion of the seat cushion 130 corresponding to the horizontal flange portion 128 and disposed at the rear of the seat cushion 130. Accordingly, the operating shaft 138 may be adjustably rotated so as to vary the height of the rear of the seat cushion 130 above the seat cushion supporting structure 142.

From the foregoing it may be appreciated that the seat cushion 130 and seat back supporting structure 118 may be shifted longitudinally of the seat cushion supporting surface 42 as the slides 116 are shifted longitudinally of the tracks 110. Further, the vertical positioning of the seat cushion 130 as well as its fore and aft inclination may be adjusted by means of the cams 132 and 140.

In operation, the supporting structure 42 is illustrated in FIG. 3 of the drawings in its uppermost limit position and in its lowermost limit position in FIGS. 4 of the drawings. It will be noted that the supporting structure 42 is in a horizontal position when disposed in these two limit positions and it is to be appreciated that the supporting structure 42 is maintained generally horizontally disposed during movement between its upper and lower limit positions.

When the weight of a person is placed upon the seat cushion 130, the supporting structure 42 is depressed downwardly which initially causes clockwise swinging movement of the crank arm 56 about the bar 50 and also about the pivot axis defined by the fastener 82. Also, initial. downward deflection of the supporting structure 42 causes counterclockwise rotation of the lever arm about the bar 40 and the pivot fastener 82. However, as the center of the bar 50 is lowered to the elevation of the pivot fastener 82 continued downward movement of the supporting structure 42 will cause clockwise swinging of the lever arm 80 about the bar 40. Thus, inasmuch as the torsion springsl02 tend to swing the lever arm 80 in a counterclockwise direction as viewed in FIGS. 3 and 4 of the drawings, the torsion springs 102 initially oppose the torsion springs 92 which tend to rotate the crank arm 56 is a counterclockwise direction as viewed in FIGS. 3 and 4 of the drawings. However, the actual counterclockwise swinging movement of the lever arm 80 relative to the bar 40 during initial lowering of the supporting structure 42 is minimal. Thus, the opposing forces of the springs 102 on the springs 92 during initial lowering of the support structure 42 is minimal although enough to appreciably reduce the forces acting upon the supporting structure 42 to raise the latter to its final uppermost position. Thus, a light person disposed on the seat cushion 130 is afforded a softer ride and the springs 102 do not begin to work in concert with the springs 92 until such time as a heavier weight person is disposed on the seat cushion 130.

By allowing the springs 102 to oppose the springs 92 during the upper third of downwardly deflecting of the supporting structure 42 and thereafter allowing the springs 102 to act in concert with the springs 92 during the final two-thirds of downward movement of the supporting structure 42, the weight of a heavier person seated on the seat cushion 130 is automatically compensated for. In addition, since the actuators for the springs 97 and 102, the crank arm 56 and the lever arm 80, are connected together by means of the pivot fastener 82 and'swing about the indicial axes of oscillation, the tensioning of the springs 92 rapidly increases as the supporting structure 42 is depressed into the lower two-third portions of such downward travel. 7 i

From FIG. 3 of the drawings it may be seen that the arm 56 has an effective length shorter than the effective length of the arm 80. The difference in the length of the arms 56 and 80 together with the relative positions of their axes of oscillation combines to enable the springs 102 to initially oppose the springs and also serves to enable the springs 92 to be less tensioned during initial depression of the assembly 42. Accordingly, a very light person may be seated upon the seat structure 10 with that light person, another than less vertical movement being experienced, being afforded substantially the same ride as a heavier person who would more greatly depress the structure 42. Further, the springs 92 and 102 may be of different gauge material and wound in different manners in order to further custom tailor the seat-support structure for use in a given environment. Also, the seat structure 10 includes means by which the pretensioning of the springs 92 and 102 may be readily adjusted. While one form of adjustment of the pretensioning of the springs 92 and 102 is illustrated and described hereinbefore, other means for adjusting the tension of the springs 92 and 102 may be provided, if desired.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to falling within the scope of the invention.

I claim:

1. A seat-mounting structure including a stationary base and generally horizontal seat-support means disposed above the base, spring controlled mounting means supporting the seatsupport means from the base for vertical movement relative taining the support means generally horizontally disposed, said spring controlled mounting means including first spring means progressively tensioned throughout movement of said seat-support means from said upper limit position to said lower limit position and second pretensioned-spring means maintained in pretensioned condition throughout movement of said seat-support means from said upper limit position to a lower intermediate position above said lower limit position and progressively further tensioned during movement of said seatsupport means downwardly from said intermediate position to said lower limit position, said seat-support means including opposite ends and opposite sides, a first pair of front to rear extending mounting levers pivotally secured at their front.

ends to opposite sides of the front end of said support means for oscillation relative thereto about first horizontal transverse axes andpivotally secured, at points forward of but adjacent their rear ends to opposite side portions of said base for oscillation about second horizontal transverse axes, a second pair of front to rear extending levers pivotally secured at their front ends to opposite sides of the front end of said support means for oscillation relative thereto about third horizontal axes and pivotally secured, at points forward of but adjacent their rear ends, to opposite side portions of said base for oscillation about fourth horizontal transverse axis, the rear ends of said first levers being spaced below the rear ends of the second levers, a pair of elongated upstanding connecting levers pivotally secured at their upper and lower ends to corresponding rear ends of said second and first pair of levers, respectively, upper and lower cross members extending between the rear ends of said first and second levers, respectively, a pair of upper and lower rearwardly and downwardly inclined and upstanding arms journaled at their upper and lower ends, respectively, from said upper and lower cross members for oscillation about horizontal transverse axes, the lower and upper ends of said upper and lower arms being pivotally secured together, said first spring means being connected between said upper cross member and said upper arm yieldingly urging said upper arm in a direction to swing its lower end downwardly and forwardly.

2. The combination of claim 1 wherein said second pretensioned-spring means is operable to oppose said first spring means when said seat-support means is disposed above said intermediate position.

3. The combination of claim 2 wherein said second spring means opposes said first spring means with decreasing force as said seat-support means is lowered from said upper limit position to said intermediate position.

4. The combination of claim 1 wherein the relative positions of the axes of oscillation of said arms relative to said cross members and the relative lengths and angular positions of said arms throughout movement of said seat-support means from its upper limit position to its lower limit positions serve to vary the tension of said spring means in a manner whereby lighter and heavier static loads on said seat-support means are afforded substantially the same cushioning effect by said seatmounting structure.

5. The combination of claim 1 wherein said second spring means is connected between said lower crossmember and said lower arm and yieldingly urging said lower arm in a direction to swing its upper end rearwardly.

6. The combination of claim 1 wherein said seat-support means includes seat cushion and seat back mounting means adjustably shiftable in fore and aft directions relative to said seat-support means.

7. The combination of claim 6 wherein said seat cushion mounting means includes means for supporting a seat cushion therefrom for adjustable vertical shifting relative to said seatcushion mounting means.

8. The combination of claim 1 wherein said first and second spring means include means for adjusting the effective tension of said spring means.

9. A seat-mounting structure including a stationary base and generally horizontal seat-support means disposed above the ase, spring controlled mounting means supporting the seatsupport means from the base for vertical movement relative thereto between upper and lower limit positions while maintaining the seat-support means generally horizontally disposed, said seat-support means including opposite ends and opposite sides, a first pair of front to rear extending mounting levers pivotally secured at their front ends to the opposite sides of the front end of said support means for oscillation relative thereto about the first horizontal transverse axes and pivotally secured, at points forward of but adjacent their rear ends to opposite side portions of said base for oscillation about second horizontal transverse axes, a second pair of front to rear-extending levers pivotally secured at their front ends to opposite sides of the front end of said support means for oscillation relative thereto about a third horizontal axes and pivotally secured, at points forward of but adjacent their rear ends to opposite side portions of said base for oscillation about fourth horizontal transverse axes, first and second crossmembers extending between the rear ends of said first and second levers, respectively, a pair of first and second lever arms journaled at one pair of corresponding ends from said first and second crossmembers and pivotally connected together at the other pair of corresponding ends thereof for relative angular displacement in response to oscillation of said levers about said second and fourth axes, and first and second spring means operatively connected between said first and second crossmembers and said lever arms yieldingly resisting relative angular displacement thereof so as to oppose downward swinging movement of the front ends of said first and second levers. 

1. A seat-mounting structure including a stationary base and generally horizontal seat-support means disposed above the base, spring controlled mounting means supporting the seat-support means from the base for vertical movement relative thereto between upper and lower limit positions while maintaining the support means generally horizontally disposed, said spring controlled mounting means including first spring means progressively tensioned throughout movement of said seat-support means from said upper limit position to said lower limit position and second pretensioned-spring means maintained in pretensioned condition throughout movement of said seat-support means from said upper limit position to a lower intermediate position above said lower limit position and progressively further tensioned during movement of said seat-support means downwardly from said intermediate position to said lower limit position, said seatsupport means including opposite ends and opposite sides, a first pair of front to rear extending mounting levers pivotally secured at their front ends to opposite sides of the front end of said support means for oscillation relative thereto about first horizontal transverse axes and pivotally secured, at points forward of but adjacent their rear ends to opposite side portions of said base for oscillation about second horizontal transverse axes, a second pair of front to rear extending levers pivotally secured at their front ends to opposite sides of the front end of said support means for oscillation relative thereto about third horizontal axes and pivotally secured, at points forward of but adjacent their rear ends, to opposite side portions of said base for oscillation about fourth horizontal transverse axis, the rear ends of said first levers being spaced below the rear ends of the second levers, a pair of elongated upstanding connecting levers pivotally secured at their upper and lower ends to corresponding rear ends of said second and first pair of levers, respectively, upper and lower cross members extending between the rear ends of said first and second levers, respectively, a pair of upper and lower rearwardly and downwardly inclined and upstanding arms journaled at their upper and lower ends, respectively, from said upper and lower cross members for oscillation about horizontal transverse axes, the lower and upper ends of said upper and lower arms being pivotally secured together, said first spring means being connected between said upper cross member and said upper arm yieldingly urging said upper arm in a direction to swing its lower end downwardly and forwardly.
 2. The combination of claim 1 wherein said second pretensioned-spring means is operable to oppose said first spring means when said seat-support means is disposed above said intermediate position.
 3. The combination of claim 2 wherein said second spring means opposes said first spring means with decreasing force as said seat-support means is lowered from said upper limit position to said intermediate position.
 4. The combination of claim 1 wherein the relative positions of the axes of oscillation of said arms relative to said cross members and the relative lengths and angular positions of said arms throughout movement of said seat-support means from its upper limit position to its lower limit positions serve to vary the tension of said spring means in a manner whereby lighter and heavier static loads on said seat-support means are afforded substantially the same cushioning effect by said seat-mounting structure.
 5. The combination of claim 1 wherein said second spring means is connected between said lower crossmember and said lower arm and yieldingly urging said lower arm in a direction to swing its upper end rearwardly.
 6. The combination of claim 1 wherein said seat-support means includes seat cushion and seat back mounting means adjustably shiftable in fore and aft directions relative to said seat-support means.
 7. The combination of claim 6 wherein said seat cushion mounting means includes means for supporting a seat cushion therefrom for adjustable vertical shifting relative to said seat-cushion mounting means.
 8. The combination of claim 1 wherein said first and second spring means include means for adjusting the effective tension of said spring means.
 9. A seat-mounting structure including a stationary base and generally horizontal seat-support means disposed above the base, spring controlled mounting means supporting the seat-support means from the base for vertical movement relative thereto between upper and lower limit positions while maintaining the seat-support means generally horizontally disposed, said seat-support means including opposite ends and opposite sides, a first pair of front to rear extending mounting levers pivotally secured at their front ends to the opposite sides of the front end of said support means for oscillation relative thereto about the first horizontal transverse axes and pivotally secured, at points forward of but adjacent their rear ends to opposite side portions of said base for oscillation about second horizontal transverse axes, a second pair of front to rear-extending levers pivotally secured at their front ends to opposite sides of the front end of said support means for oscillation relative thereto about a third horizontal axes and pivotally secured, at points forward of but adjacent their rear ends to opposite side portions of said base for oscillation about fourth horizontal transverse axes, first and second crossmembers extending between the rear ends of said first and second levers, respectively, a pair of first and second lever arms journaled at one pair of corresponding ends from said first and second crossmembers and pivotally connected together at the other pair of corresponding ends thereof for relative angular displacement in response to oscillation of said levers about said second and fourth axes, and first and second spring means operatively connected between said first and second crossmembers and said lever arms yieldingly resisting relative angular displacement thereof so as to oppose downward swinging movement of the front ends of said first and second levers. 